The present invention relates to polymerization processes, and more particularly, to gas phase polymerization processes that utilize bimetallic catalyst systems.
Bimodal polymers produced using two or more different catalyst typesxe2x80x94bimetallic catalystsxe2x80x94are of increasing interest, especially in producing polyethylene and other polyolefins. See, for example, U.S. Pat. No. 5,525,678. However, problems exist in using these bimetallic catalysts, especially in the gas phase. One problem is catalyst activity, which should be as high as possible in order to economize the process, as catalysts costs are significant.
One method of improving catalyst efficiency in gas phase processes is to increase the residence time of the catalyst in the fluidized bed of the gas phase reactor. Residence time can be increased by increasing the fluidized bulk density of the system, or lowering the voidage of the system. There are many factors that can influence the residence time of the catalyst. However, determining the right combination of factors for a given catalyst is complex and costly, and is compounded by the presence of a bimetallic system. What is needed is a method of improving the economy of producing bimodal polymers. The present invention is directed towards solving this and other problems.
The present invention provides a polymerization process, gas phase polymerization processes in one embodiment. At least one specific embodiment of the invention relates to a gas phase polymerization process for producing a polyolefin composition, including passing a gaseous stream containing hydrogen gas and one or more monomers, including ethylene monomers, through a reactor that includes a fluidized bed, under reactive conditions, in the presence of a catalyst that includes metallocene, to provide a polyolefin composition, wherein: (a) the fluidized bulk density is 60% or more of the settled bulk density; (b) the reactor temperature is 100xc2x0 C. or below; and (c) the molar ratio of hydrogen gas to ethylene in the gaseous stream is 0.015 or below.
In particular embodiments, the fluidized bulk density is 65% or more of the settled bulk density. In other embodiments, the fluidized bulk density is 70% or more of the settled bulk density.
In yet a more particular embodiment, (a) the reactor temperature is from 80xc2x0 C. to 97xc2x0 C.; and (b) the molar ratio of hydrogen gas to ethylene in the gaseous stream is from 0.003 to 0.009.
In yet another embodiment, the molar ratio of hydrogen gas to ethylene in the gaseous stream is less than 0.008. In a more particular embodiment, the molar ratio of hydrogen gas to ethylene in the gaseous stream can be from 0.003 to 0.008. In yet a more particular embodiment, the molar ratio of hydrogen gas to ethylene in the gaseous stream can be from 0.003 to 0.007. And in yet a more particular embodiment, the molar ratio of hydrogen gas to ethylene in the gaseous stream is from 0.003 to 0.006.
In one embodiment of the processes disclosed herein, the reactor temperature is maintained at 96xc2x0 C. or below. Alternatively, the reactor temperature may be maintained at 95xc2x0 C. or below in another embodiment. Also, the reactor temperature may maintained at 94xc2x0 C. or below in yet another embodiment.
In a particular embodiment, the catalyst is a supported bimetallic catalyst. Even more particularly, the catalyst is a supported bimetallic catalyst that includes a metallocene catalyst compound. Even more particularly, the catalyst is a supported bimetallic catalyst that includes a metallocene catalyst compound having at least one fluoride or fluorine containing leaving group.
In one embodiment of the processes disclosed herein, the polyolefin composition resulting from the polymerization process is a bimodal polyolefin composition that includes a high molecular weight polyolefin component and a low molecular weight polyolefin component.
In one embodiment of the processes disclosed herein, the catalyst includes a support material comprising silica dehydrated at a temperature of 800xc2x0 C. or more.
General Definitions
As used herein, in reference to Periodic Table xe2x80x9cGroupsxe2x80x9d of Elements, the xe2x80x9cnewxe2x80x9d numbering scheme for the Periodic Table Groups are used as in the CRC Handbook of Chemistry and Physics (David R. Lide ed., CRC Press 81st ed. 2000).
As used herein, the phrase xe2x80x9ccatalyst systemxe2x80x9d includes at least one xe2x80x9ccatalyst componentxe2x80x9d and at least one xe2x80x9cactivatorxe2x80x9d, both of which are described further herein. The catalyst system may also include other components, such as supports, etc., and is not limited to the catalyst component and/or activator alone or in combination. The catalyst system may include any number of catalyst components in any combination as described herein, as well as any activator in any combination as described herein.
As used herein, the phrase xe2x80x9ccatalyst compoundxe2x80x9d includes any compound that, once appropriately activated, is capable of catalyzing the polymerization or oligomerization of olefins, the catalyst compound comprising at least one Group 3 to Group 12 atom, and optionally at least one leaving group bound thereto.
As used herein, the phrase xe2x80x9cleaving groupxe2x80x9d refers to one or more chemical moieties bound to the metal center of the catalyst component that can be abstracted from the catalyst component by an activator, thus producing the species active towards olefin polymerization or oligomerization. The activator is described further below.
As used herein, the term xe2x80x9cfluorinated catalyst componentxe2x80x9d means a catalyst compound having at least one fluoride or fluorine containing leaving group, preferably a metallocene or metallocene-type catalyst compound having at least one fluoride or fluorine containing leaving group.
As used herein, a xe2x80x9chydrocarbylxe2x80x9d includes aliphatic, cyclic, olefinic, acetylenic and aromatic radicals (i.e., hydrocarbon radicals) comprising hydrogen and carbon that are deficient by one hydrogen. A xe2x80x9chydrocarbylenexe2x80x9d is deficient by two hydrogens.
As used herein, an xe2x80x9calkylxe2x80x9d includes linear, branched and cyclic paraffin radicals that are deficient by one hydrogen. Thus, for example, a xe2x80x94CH3 group (xe2x80x9cmethylxe2x80x9d) and a CH3CH2xe2x80x94 group (xe2x80x9cethylxe2x80x9d) are examples of alkyls.
As used herein, an xe2x80x9calkenylxe2x80x9d includes linear, branched and cyclic olefin radicals that are deficient by one hydrogen; alkynyl radicals include linear, branched and cyclic acetylene radicals deficient by one hydrogen radical.
As used herein, xe2x80x9carylxe2x80x9d groups includes phenyl, naphthyl, pyridyl and other radicals whose molecules have the ring structure characteristic of benzene, naphthylene, phenanthrene, anthracene, etc. For example, a C6H5xe2x88x92 aromatic structure is an xe2x80x9cphenylxe2x80x9d, a C6H42xe2x88x92 aromatic structure is an xe2x80x9cphenylenexe2x80x9d. An xe2x80x9carylalkylxe2x80x9d group is an alkyl group having an aryl group pendant therefrom; an xe2x80x9calkylarylxe2x80x9d is an aryl group having one or more alkyl groups pendant therefrom.
As used herein, an xe2x80x9calkylenexe2x80x9d includes linear, branched and cyclic hydrocarbon radicals deficient by two hydrogens. Thus, xe2x80x94CH2xe2x80x94 (xe2x80x9cmethylenexe2x80x9d) and xe2x80x94CH2CH2xe2x80x94 (xe2x80x9cethylenexe2x80x9d) are examples of alkylene groups. Other groups deficient by two hydrogen radicals include xe2x80x9carylenexe2x80x9d and xe2x80x9calkenylenexe2x80x9d.
As used herein, the phrase xe2x80x9cheteroatomxe2x80x9d includes any atom other than carbon and hydrogen that can be bound to carbon, and in one embodiment is selected from the group consisting of B, Al, Si, Ge, N, P, O, and S. A xe2x80x9cheteroatom-containing groupxe2x80x9d is a hydrocarbon radical that contains a heteroatom and may contain one or more of the same or different heteroatoms, and from 1 to 3 heteroatoms in a particular embodiment. Non-limiting examples of heteroatom-containing groups include radicals of imines, amines, oxides, phosphines, ethers, ketones, oxoazolines heterocyclics, oxazolines, thioethers, and the like.
As used herein, an xe2x80x9calkylcarboxylatexe2x80x9d, xe2x80x9carylcarboxylatexe2x80x9d, and xe2x80x9calkylarylcarboxylatexe2x80x9d is an alkyl, aryl, and alkylaryl, respectively, that possesses a carboxyl group in any position. Examples include C6H5CH2C(O)Oxe2x88x92, CH3C(O)Oxe2x88x92, etc.
As used herein, the term xe2x80x9csubstitutedxe2x80x9d means that the group following that term possesses at least one moiety in place of one or more hydrogens in any position, the moieties selected from such groups as halogen radicals (esp., Cl, F, Br), hydroxyl groups, carbonyl groups, carboxyl groups, amine groups, phosphine groups, alkoxy groups, phenyl groups, naphthyl groups, C1 to C10 alkyl groups, C2 to C10 alkenyl groups, and combinations thereof. Examples of substituted alkyls and aryls includes, but are not limited to, acyl radicals, alkylamino radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- and dialkyl- carbamoyl radicals, acyloxy radicals, acylamino radicals, arylamino radicals, and combinations thereof.
As used herein, structural formulas are employed as is commonly understood in the chemical arts; lines (xe2x80x9cxe2x80x94xe2x80x9d) used to represent associations between a metal atom (xe2x80x9cMxe2x80x9d, Group 3 to Group 12 atoms) and a ligand or ligand atom (e.g., cyclopentadienyl, nitrogen, oxygen, halogen ions, alkyl, etc.), as well as the phrases xe2x80x9cassociated withxe2x80x9d, xe2x80x9cbonded toxe2x80x9d and xe2x80x9cbondingxe2x80x9d, are not limited to representing a certain type of chemical bond, as these lines and phrases are meant to represent a xe2x80x9cchemical bondxe2x80x9d; a xe2x80x9cchemical bondxe2x80x9d defined as an attractive force between atoms that is strong enough to permit the combined aggregate to function as a unit, or xe2x80x9ccompoundxe2x80x9d.
A certain stereochemistry for a given structure or part of a structure should not be implied unless so stated for a given structure or apparent by use of commonly used bonding symbols such as by dashed lines and/or heavy lines.
Unless stated otherwise, no embodiment of the present invention is herein limited to the oxidation state of the metal atom xe2x80x9cMxe2x80x9d as defined below in the individual descriptions and examples that follow. The ligation of the metal atom xe2x80x9cMxe2x80x9d is such that the compounds described herein are neutral, unless otherwise indicated.
As used herein, the term xe2x80x9cbimodal,xe2x80x9d when used to describe a polymer or polymer composition (e.g., polyolefins such as polypropylene or polyethylene, or other homopolymers, copolymers or terpolymers) means xe2x80x9cbimodal molecular weight distribution,xe2x80x9d which is understood as having the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents. For example, a single composition that includes polyolefins with at least one identifiable high molecular weight distribution and polyolefins with at least one identifiable low molecular weight distribution is considered to be a xe2x80x9cbimodalxe2x80x9d polyolefin, as that term is used herein. In a particular embodiment, other than having different molecular weights, the high molecular weight polyolefin and the low molecular weight polyolefin are essentially the same type of polymer, for example, polypropylene or polyethylene.
As used herein, the term xe2x80x9cproductivityxe2x80x9d means the weight of polymer produced per weight of the catalyst used in the polymerization process (e.g., grams polymer/gram catalyst).
As used herein, the term xe2x80x9cdehydratedxe2x80x9d is understood as having the broadest definition persons in the pertinent art have given that term in describing catalyst support materials, for example, silica, as reflected in printed publications and issued patents, and includes any material, for example, a support particle, from which a majority of the contained/adsorbed water has been removed.
Gas-phase Polymerization using Bimetallic Catalysts
The present invention provides a gas phase polymerization process comprising combining hydrogen, ethylene and a bimetallic catalyst system in a reactor, a single reactor in a particular embodiment, the components combined in the fluidized bed of the gas phase reactor; characterized in that the bimetallic catalyst system includes at least one metallocene catalyst component. Stated alternately, the present invention provides a method of controlling the voidage (or fluidized bed density) of a fluidized bed gas phase reactor during polyolefin polymerization processes utilizing bimetallic catalysts. The voidage (or fluidized bulk density) is controlled in one embodiment by adjusting the hydrogen level relative to the ethylene monomer level introduced into the reactor, and by adjusting the reactor temperature in another embodiment, or both.
By xe2x80x9csingle reactorxe2x80x9d, it is meant that the entire polymerization reaction takes place in one reactor, wherein catalyst and monomers etc. flow into a reactor vessel, and polymer resin flows out, where the resin can be processed such as by deashing, extrusion, etc.
The bimetallic catalyst system comprises at least one metallocene catalyst component as described herein, and is a bridged or unbridged sandwich compound in a particular embodiment, and comprises one or more fluoride ion leaving groups in a more particular embodiment.
Each component of the invention is set out below in its various embodiments. The embodiments as described can be combined in any number of ways to arrive at the invention.
Bimetallic Catalyst
As used herein, the term xe2x80x9cbimetallic catalystxe2x80x9d or xe2x80x9cbimetallic catalyst systemxe2x80x9d refers to two or more catalyst components used in combination with at least one activator, and optionally a support material, that is useful in polymerizing olefins. The xe2x80x9csupported bimetallic catalystxe2x80x9d or xe2x80x9csupported bimetallic catalyst compositionxe2x80x9d refers to the bimetallic catalyst system as used in combination with a support material, wherein one or more of the components that make up the bimetallic catalyst system may be bound to the support. In a particular embodiment, the bimetallic catalyst of the invention includes two catalyst components. In a more particular embodiment, the bimetallic catalyst component includes a xe2x80x9cfirst catalyst componentxe2x80x9d and a xe2x80x9csecond catalyst componentxe2x80x9d.
As used herein, the term xe2x80x9cfirst catalyst componentxe2x80x9d refers to any catalyst component other than the second catalyst component. Preferably, the first catalyst component is a non-metallocene catalyst component, examples of which include titanium or vanadium based Ziegler-Natta catalysts compounds as described further herein.
As used herein, the term xe2x80x9cnon-metallocene compoundxe2x80x9d refers any catalyst that is neither a metallocene nor one of the metallocene-type catalyst compounds identified below.
As used herein, the term xe2x80x9csecond catalyst componentxe2x80x9d refers to any catalyst that is different from a first catalyst component, a metallocene catalyst component in a particular embodiment. In a particular embodiment, the second catalyst component includes a zirconium metallocene component.
Certain embodiments of the present invention involve contacting monomers with a bimetallic catalyst component, also referred to herein as simply a bimetallic catalyst. In a particular embodiment, each different catalyst compound that comprises the bimetallic catalyst resides, or is supported on a single type of support such that, on average, each particle of support material includes both the first and second catalyst components. In another embodiment, the first catalyst component is supported separately from the second catalyst component such that on average any given particle of support material comprises only the first or the second catalyst component. In this later embodiment, each supported catalyst may be introduced into the polymerization reactor sequentially in any order, alternately in parts, or simultaneously.
In a particular embodiment, the first catalyst component includes a titanium non-metallocene catalyst component, from which a higher molecular weight resin (e.g.,  greater than ca 100,000 amu) can be produced. In a particular embodiment, the second catalyst component includes a metallocene component, from which a lower molecular weight resin (e.g.,  less than ca 100,000 amu) can be produced. Accordingly, polymerization in the presence of the first and second catalyst components provides a bimodal polyolefin composition that includes a low molecular weight component and a high molecular weight component. The two catalyst components reside on a single support particle in a particular embodiment, and they can be affixed to the support in a variety of ways.
In one embodiment, an xe2x80x9cenhanced silicaxe2x80x9d is prepared as described herein and constitutes the support; the first catalyst component is a non-metallocene compound that is first combined with the enhanced silica, to provide a supported non-metallocene composition; the supported non-metallocene composition is combined with the second catalyst component, for example, a fluorided metallocene (a metallocene having at least one fluorine ion leaving group), resulting in a fluorinated bimetallic catalyst composition having enhanced productivity when used in production of a bimodal polyolefin composition.
Various methods of affixing two different catalyst components (albeit a different combination of catalysts) to a support can be used. In general, one procedure for preparing a supported bimetallic catalyst can include providing a supported first catalyst component, contacting a slurry that includes the first catalyst component in a non-polar hydrocarbon with a solution that includes the second catalyst component, which may also include an activator, and drying the resulting product that includes the first and second catalyst components and recovering a bimetallic catalyst composition.
First Catalyst Component
As noted above, the bimetallic catalyst composition includes a first catalyst component, which is (or includes) a non-metallocene compound. However, it is contemplated that for certain applications the first catalyst component may alternatively be a metallocene compound, or even one of the metallocene-type catalyst compounds identified below that is different in structure from the second catalyst component as described herein. In a particular embodiment, the first catalyst component is a Ziegler-Natta catalyst compound. Ziegler-Natta catalyst components are well known in the art and described, for example, in Ziegler Catalysts 363-386 (G. Fink, R. Mulhaupt and H. H. Brintzinger, eds., Springer-Verlag 1995). Examples of such catalysts include those comprising TiCl4 and other such transition metal oxides and chlorides.
The first catalyst component is combined with a support material in one embodiment, either with or without the second catalyst component. The first catalyst component can be combined with, placed on or otherwise affixed to a support in a variety of ways. In one of those ways, a slurry of the support in a suitable non-polar hydrocarbon diluent is contacted with an organomagnesium compound, which then dissolves in the non-polar hydrocarbon diluent of the slurry to form a solution from which the organomagnesium compound is then deposited onto the carrier. The organomagnesium compound can be represented by the formula RMgRxe2x80x2, where Rxe2x80x2 and R are the same or different C2-C12 alkyl groups, or C4-C10 alkyl groups, or C4-C8 alkyl groups. In at least one specific embodiment, the organomagnesium compound is dibutyl magnesium. In one embodiment, the amount of organomagnesium compound included in the silica slurry is only that which will be deposited, physically or chemically, onto the support, for example, being bound to the hydoxyl groups on the support, and no more than that amount, since any excess organomagnesium compound may cause undesirable side reactions. Routine experimentation can be used to determine the optimum amount of organomagnesium compound. For example, the organomagnesium compound can be added to the slurry while stirring the slurry, until the organomagnesium compound is detected in the support solvent. Alternatively, the organomagnesium compound can be added in excess of the amount that is deposited onto the support, in which case any undeposited excess amount can be removed by filtration and washing. The amount of organomagnesium compound (moles) based on the amount of dehydrated silica (grams) generally range from 0.2 mmol/g to 2 mmol/g in a particular embodiment.
Optionally, the organomagnesium compound-treated slurry is contacted with an electron donor, such as tetraethylorthosiloxane (TEOS) or an organic alcohol Rxe2x80x3OH, where Rxe2x80x3 is a C1-C12 alkyl group, or a C1 to C8 alkyl group, or a C2 to C4 alkyl group. In a particular embodiment, Rxe2x80x3OH is n-butanol. The amount of alcohol used in an amount effective to provide an Rxe2x80x3OH:Mg mol/mol ratio of from 0.2 to 1.5, or from 0.4 to 1.2, or from 0.6 to 1.1, or from 0.9 to 1.0.
The organomagnesium and alcohol-treated slurry is contacted with a non-metallocene transition metal compound. Suitable non-metallocene transition metal compounds are compounds of Group 4 and 5 metals that are soluble in the non-polar hydrocarbon used to form the silica slurry in a particular embodiment. Suitable non-metallocene transition metal compounds include, for example, titanium and vanadium halides, oxyhalides or alkoxyhalides, such as titanium tetrachloride (TiCl4), vanadium tetrachloride (VCl4) and vanadium oxytrichloride (VOCl3), and titanium and vanadium alkoxides, wherein the alkoxide moiety has a branched or unbranched alkyl group of 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms. Mixtures of such transition metal compounds may also be used. The amount of non-metallocene transition metal compound used is sufficient to give a transition metal to magnesium mol/mol ratio of from 0.3 to 1.5, or from 0.5 to 0.8. The diluent can then be removed in a conventional manner, such as by evaporation or filtering, to obtain the dry, supported first catalyst component.
The first and second catalyst components may be contacted with the support in any order. In a particular embodiment of the invention, the first catalyst component is reacted first with the support as described above, followed by contacting this supported first catalyst component with a second catalyst component.
Second Catalyst Component
The bimetallic catalyst system useful in the present invention includes a second catalyst component comprising at least one metallocene catalyst component as described herein. Metallocene catalyst compounds are generally described throughout in, for example, 1 and 2 Metallocene-Based Polyolefins (John Scheirs and W. Kaminsky eds., John Wiley and Sons, Ltd. 2000); G. G. Hlatky in 181 Coordination Chem. Rev. 243-296 (1999) and in particular, for use in the synthesis of polyethylene in 1 Metallocene-Based Polyolefins 261-377 (2000). The metallocene catalyst compounds as described herein include xe2x80x9chalf sandwichxe2x80x9d and xe2x80x9cfull sandwichxe2x80x9d compounds having one or more Cp ligands (cyclopentadienyl and ligands isolobal to cyclopentadienyl) bound to at least one Group 3 to Group 12 metal atom, and one or more leaving group(s) bound to the at least one metal atom. Hereinafter, these compounds will be referred to as xe2x80x9cmetallocenesxe2x80x9d or xe2x80x9cmetallocene catalyst componentsxe2x80x9d. The metallocene catalyst component is supported on a support material in a particular embodiment as described further below, and may be supported with or without the first catalyst component, with the first catalyst component in a particular embodiment.
The Cp ligands are typically xcfx80-bonded and/or fused ring(s) or ring systems. The ring(s) or ring system(s) typically comprise atoms selected from the group consisting of Groups 13 to 16 atoms, and more particularly, the atoms that make up the Cp ligands are selected from the group consisting of carbon, nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron and aluminum and combinations thereof, wherein carbon makes up at least 50% of the ring members. Even more particularly, the Cp ligand(s) are selected from the group consisting of substituted and unsubstituted cyclopentadienyl ligands and ligands isolobal to cyclopentadienyl, non-limiting examples of which include cyclopentadienyl, indenyl, fluorenyl and other structures. Further non-limiting examples of such ligands include cyclopentadienyl, cyclopentaphenanthreneyl, indenyl, benzindenyl, fluorenyl, octahydrofluorenyl, cyclooctatetraenyl, cyclopentacyclododecene, phenanthrindenyl, 3,4-benzofluorenyl, 9-phenylfluorenyl, 8-H-cyclopent[a]acenaphthylenyl, 7H-dibenzofluorenyl, indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl, hydrogenated versions thereof (e.g., 4,5,6,7-tetrahydroindenyl, or xe2x80x9cH4Indxe2x80x9d), substituted versions thereof, and heterocyclic versions thereof. In a particular embodiment, the metallocenes useful in the present invention are selected from those including one or two, two in a more particular embodiment, of the same or different Cp rings selected from the group consisting of cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl, and substituted versions thereof.
The metal atom xe2x80x9cMxe2x80x9d of the metallocene catalyst compound, as described throughout the specification and claims, may be selected from the group consisting of Groups 3 through 12 atoms and lanthanide Group atoms in one embodiment; and selected from the group consisting of Groups 3 through 10 atoms in a more particular embodiment, and selected from the group consisting of Sc, Ti, Zr, Hf, V, Nb, Ta, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, and Ni in yet a more particular embodiment; and selected from the group consisting of Groups 4, 5 and 6 atoms in yet a more particular embodiment, and a Ti, Zr, Hf atoms in yet a more particular embodiment, and Zr in yet a more particular embodiment. The oxidation state of the metal atom xe2x80x9cMxe2x80x9d may range from 0 to +7 in one embodiment; and in a more particular embodiment, is +1, +2, +3, +4 or +5; and in yet a more particular embodiment is +2, +3 or +4. The groups bound the metal atom xe2x80x9cMxe2x80x9d are such that the compounds described below in the formulas and structures are electrically neutral, unless otherwise indicated. The Cp ligand(s) form at least one chemical bond with the metal atom M to form the xe2x80x9cmetallocene catalyst compoundxe2x80x9d. The Cp ligands are distinct from the leaving groups bound to the catalyst compound in that they are not highly susceptible to substitution/abstraction reactions.
In one aspect of the invention, the one or more metallocene catalyst components of the invention are represented by the formula (I):
CpACpBMXnxe2x80x83xe2x80x83(I)
wherein M is as described above; each X is chemically bonded to M; each Cp group is chemically bonded to M; and n is an integer from 0 to 4, and either 1 or 2 in a particular embodiment.
The ligands represented by CpA and CpB in formula (I) may be the same or different cyclopentadienyl ligands or ligands isolobal to cyclopentadienyl, either or both of which may contain heteroatoms and either or both of which may be substituted by a group R. In one embodiment, CpA and CpB are independently selected from the group consisting of cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, and substituted derivatives of each.
Independently, each CpA and CpB of formula (I) may be unsubstituted or substituted with any one or combination of substituent groups R. Non-limiting examples of substituent groups R as used in structure (I) as well as ring substituents in structures (Va-d) include groups selected from the group consisting of hydrogen radicals, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, and combinations thereof.
More particular non-limiting examples of alkyl substituents R associated with formula (I) through (V) include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl, phenyl, methylphenyl, and tert-butylphenyl groups and the like, including all their isomers, for example tertiarybutyl, isopropyl, and the like. Other possible radicals include substituted alkyls and aryls such as, for example, fluoromethyl, fluroethyl, difluroethyl, iodopropyl, bromohexyl, chlorobenzyl and hydrocarbyl substituted organometalloid radicals including trimethylsilyl, trimethylgermyl, methyldiethylsilyl and the like; and halocarbyl-substituted organometalloid radicals including tris(trifluoromethyl)silyl, methylbis(difluoromethyl)silyl, bromomethyldimethylgermyl and the like; and disubstituted boron radicals including dimethylboron for example; and disubstituted Group 15 radicals including dimethylamine, dimethylphosphine, diphenylamine, methylphenylphosphine, Group 16 radicals including methoxy, ethoxy, propoxy, phenoxy, methylsulfide and ethylsulfide. Other substituents R include olefins such as but not limited to olefinically unsaturated substituents including vinyl-terminated ligands, for example 3-butenyl, 2-propenyl, 5-hexenyl and the like. In one embodiment, at least two R groups, two adjacent R groups in one embodiment, are joined to form a ring structure having from 3 to 30 atoms selected from the group consisting of carbon, nitrogen, oxygen, phosphorous, silicon, germanium, aluminum, boron and combinations thereof. Also, a substituent group R group such as 1-butanyl may form a bonding association to the element M.
Each X in the formula (I) above and for the formulas/structures (II) through (V) below is independently selected from the group consisting of: any leaving group in one embodiment; halogen ions, hydrides, C1 to C12 alkyls, C2 to C12 alkenyls, C6 to C12 aryls, C7 to C20 alkylaryls, C1 to C12 alkoxys, C6 to C16 aryloxys, C7 to C18 alkylaryloxys, C1 to C12 fluoroalkyls, C6 to C12 fluoroaryls, and C1 to C12 heteroatom-containing hydrocarbons and substituted derivatives thereof in a more particular embodiment; hydride, halogen ions, C1 to C6 alkyls, C2 to C6 alkenyls, C7 to C18 alkylaryls, C1 to C6 alkoxys, C6 to C14 aryloxys, C7 to C16 alkylaryloxys, C1 to C6 alkylcarboxylates, C1 to C6 fluorinated alkylcarboxylates, C6 to C12 arylcarboxylates, C7 to C18 alkylarylcarboxylates, C1 to C6 fluoroalkyls, C2 to C6 fluoroalkenyls, and C7 to C18 fluoroalkylaryls in yet a more particular embodiment; hydride, chloride, fluoride, methyl, phenyl, phenoxy, benzoxy, tosyl, fluoromethyls and fluorophenyls in yet a more particular embodiment; C1 to C12 alkyls, C2 to C12 alkenyls, C6 to C12 aryls, C7 to C20 alkylaryls, substituted C1 to C12 alkyls, substituted C6 to C12 aryls, substituted C7 to C20 alkylaryls and C1 to C12 heteroatom-containing alkyls, C1 to C12 heteroatom-containing aryls and C1 to C12 heteroatom-containing alkylaryls in yet a more particular embodiment; chloride, fluoride, C1 to C6 alkyls, C2 to C6 alkenyls, C7 to C18 alkylaryls, halogenated C1 to C6 alkyls, halogenated C2 to C6 alkenyls, and halogenated C7 to C18 alkylaryls in yet a more particular embodiment; fluoride, methyl, ethyl, propyl, phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, fluoromethyls (mono-, di- and trifluoromethyls) and fluorophenyls (mono-, di-, tri-, tetra- and pentafluorophenyls) in yet a more particular embodiment; and fluoride in yet a more particular embodiment.
Other non-limiting examples of X groups in formula (I) include amines, phosphines, ethers, carboxylates, dienes, hydrocarbon radicals having from 1 to 20 carbon atoms, fluorinated hydrocarbon radicals (e.g., xe2x80x94C6F5 (pentafluorophenyl)), fluorinated alkylcarboxylates (e.g., CF3C(O)Oxe2x88x92), hydrides and halogen ions and combinations thereof. Other examples of X ligands include alkyl groups such as cyclobutyl, cyclohexyl, methyl, heptyl, tolyl, trifluoromethyl, tetramethylene, pentamethylene, methylidene, methyoxy, ethyoxy, propoxy, phenoxy, bis(N-methylanilide), dimethylamide, dimethylphosphide radicals and the like. In one embodiment, two or more X""s form a part of a fused ring or ring system.
In another aspect of the invention, the metallocene catalyst component includes those of formula (I) where CpA and CpB are bridged to each other by at least one bridging group, (A), such that the structure is represented by formula (II):
CpA(A)CpBMXnxe2x80x83xe2x80x83(II)
These bridged compounds represented by formula (II) are known as xe2x80x9cbridged metallocenesxe2x80x9d. CpA, CpB, M, X and n in structure (II) are as defined above for formula (I); and wherein each Cp ligand is chemically bonded to M, and (A) is chemically bonded to each Cp. Non-limiting examples of bridging group (A) include divalent hydrocarbon groups containing at least one Group 13 to 16 atom, such as but not limited to at least one of a carbon, oxygen, nitrogen, silicon, aluminum, boron, germanium and tin atom and combinations thereof; wherein the heteroatom may also be C1 to C12 alkyl or aryl substituted to satisfy neutral valency. The bridging group (A) may also contain substituent groups R as defined above (for formula (I)) including halogen radicals and iron. More particular non-limiting examples of bridging group (A) are represented by C1 to C6 alkylenes, substituted C1 to C6 alkylenes, oxygen, sulfur, Rxe2x80x22Cxe2x95x90, Rxe2x80x22Sixe2x95x90, xe2x80x94Si(Rxe2x80x2)2Si(Rxe2x80x22xe2x80x94, Rxe2x80x22Gexe2x95x90, Rxe2x80x2Pxe2x95x90 (wherein xe2x80x9cxe2x95x90xe2x80x9d represents two chemical bonds), where Rxe2x80x2 is independently selected from the group consisting of hydride, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl-substituted organometalloid, halocarbyl-substituted organometalloid, disubstituted boron, disubstituted Group 15 atoms, substituted Group 16 atoms, and halogen radical; and wherein two or more Rxe2x80x2 may be joined to form a ring or ring system. In one embodiment, the bridged metallocene catalyst component of formula (II) has two or more bridging groups (A).
Other non-limiting examples of bridging group (A) include methylene, ethylene, ethylidene, propylidene, isopropylidene, diphenylmethylene, 1,2-dimethylethylene, 1,2-diphenylethylene, 1,1,2,2-tetramethylethylene, dimethylsilyl, diethylsilyl, methyl-ethylsilyl, trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di(n-butyl)silyl, di(n-propyl)silyl, di(i-propyl)silyl, di(n-hexyl)silyl, dicyclohexylsilyl, diphenylsilyl, cyclohexylphenylsilyl, t-butylcyclohexylsilyl, di(t-butylphenyl)silyl, di(p-tolyl)silyl and the corresponding moieties wherein the Si atom is replaced by a Ge or a C atom; dimethylsilyl, diethylsilyl, dimethylgermyl and diethylgermyl.
In another embodiment, bridging group (A) may also be cyclic, comprising, for example 4 to 10, 5 to 7 ring members in a more particular embodiment. The ring members may be selected from the elements mentioned above, from one or more of B, C, Si, Ge, N and O in a particular embodiment. Non-limiting examples of ring structures which may be present as or part of the bridging moiety are cyclobutylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene and the corresponding rings where one or two carbon atoms are replaced by at least one of Si, Ge, N and O, in particular, Si and Ge. The bonding arrangement between the ring and the Cp groups may be either cis-, trans-, or a combination.
The cyclic bridging groups (A) may be saturated or unsaturated and/or carry one or more substituents and/or be fused to one or more other ring structures. If present, the one or more substituents are selected from the group consisting of hydrocarbyl (e.g., alkyl such as methyl) and halogen (e.g., F, Cl) in one embodiment. The one or more Cp groups which the above cyclic bridging moieties may optionally be fused to may be saturated or unsaturated and are selected from the group consisting of those having 4 to 10, more particularly 5, 6 or 7 ring members (selected from the group consisting of C, N, O and S in a particular embodiment) such as, for example, cyclopentyl, cyclohexyl and phenyl. Moreover, these ring structures may themselves be fused such as, for example, in the case of a naphthyl group. Moreover, these (optionally fused) ring structures may carry one or more substituents. Illustrative, non-limiting examples of these substituents are hydrocarbyl (particularly alkyl) groups and halogen atoms.
The ligands CpA and CpB of formulae (I) and (II) are different from each other in one embodiment, and the same in another embodiment.
In yet another aspect of the invention, the metallocene catalyst components include bridged mono-ligand metallocene compounds (e.g., mono cyclopentadienyl catalyst components). In this embodiment, the at least one metallocene catalyst component is a bridged xe2x80x9chalf-sandwichxe2x80x9d metallocene represented by the formula (III):
CpA(A)QMXnxe2x80x83xe2x80x83(III)
wherein CpA is defined above and is bound to M; (A) is a bridging group bonded to Q and CpA; and wherein an atom from the Q group is bonded to M; and n is an integer 0, 1 or 2. In formula (III) above, CpA, (A) and Q may form a fused ring system. The X groups and n of formula (III) are as defined above in formula (I) and (II). In one embodiment, CpA is selected from the group consisting of cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, substituted versions thereof, and combinations thereof.
In formula (III), Q is a heteroatom-containing ligand in which the bonding atom (the atom that is bonded with the metal M) is selected from the group consisting of Group 15 atoms and Group 16 atoms in one embodiment, and selected from the group consisting of nitrogen, phosphorus, oxygen or sulfur atom in a more particular embodiment, and nitrogen and oxygen in yet a more particular embodiment. Non-limiting examples of Q groups include alkylamines, arylamines, mercapto compounds, ethoxy compounds, carboxylates (e.g., pivalate), carbamates, azenyl, azulene, pentalene, phosphoyl, phosphinimine, pyrrolyl, pyrozolyl, carbazolyl, borabenzene other compounds comprising Group 15 and Group 16 atoms capable of bonding with M.
In yet another aspect of the invention, the at least one metallocene catalyst component is an unbridged xe2x80x9chalf sandwichxe2x80x9d metallocene represented by the formula (IVa):
CpAMQqXnxe2x80x83xe2x80x83(IVa)
wherein CpA is defined as for the Cp groups in (I) and is a ligand that is bonded to M; each Q is independently bonded to M; X is a leaving group as described above in (I); n ranges from 0 to 3, and is 0 or 3 in one embodiment; q ranges from 0 to 3, and is 0 or 3 in one embodiment. In one embodiment, CpA is selected from the group consisting of cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, substituted version thereof, and combinations thereof.
In formula (IVa), Q is selected from the group consisting of ROOxe2x88x92, ROxe2x80x94, R(O)xe2x80x94, xe2x80x94NRxe2x80x94, xe2x80x94CR2xe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NR2, xe2x80x94CR3, xe2x80x94SR, xe2x80x94SiR3, xe2x80x94PR2, xe2x80x94H, and substituted and unsubstituted aryl groups, wherein R is selected from the group consisting of C1 to C6 alkyls, C6 to C12 aryls, C1 to C6 alkylamines, C6 to C12 alkylarylamines, C1 to C6 alkoxys, C6 to C12 aryloxys, and the like. Non-limiting examples of Q include C1 to C12 carbamates, C1 to C12 carboxylates (e.g., pivalate), C2 to C20 allyls, and C2 to C20 heteroallyl moieties.
Described another way, the xe2x80x9chalf sandwichxe2x80x9d metallocenes above can be described as in formula (IVb), such as described in, for example, U.S. Pat. No. 6,069,213:
CpAM(Q2GZ)Xn orxe2x80x83xe2x80x83(IVb)
T(CpAM(Q2GZ)Xn)m
wherein M, CpA, X and n are as defined above;
Q2GZ forms a polydentate ligand unit (e.g., pivalate), wherein at least one of the Q groups form a bond with M, and is defined such that each Q is independently selected from the group consisting of xe2x80x94Oxe2x80x94, NRxe2x80x94, xe2x80x94CR2xe2x80x94 and xe2x80x94Sxe2x80x94; G is either carbon or silicon; and Z is selected from the group consisting of R, xe2x80x94OR, xe2x80x94NR2, xe2x80x94CR3, xe2x80x94SR, xe2x80x94SiR3, xe2x80x94PR2, and hydride, providing that when Q is xe2x80x94NRxe2x80x94, then Z is selected from the group consisting of xe2x80x94OR, xe2x80x94NR2, xe2x80x94SR, xe2x80x94SiR3, xe2x80x94PR2; and provided that neutral valency for Q is satisfied by Z; and wherein each R is independently selected from the group consisting of C1 to C10 heteroatom containing groups, C1 to C10 alkyls, C6 to C12 aryls, C6 to C12 alkylaryls, C1 to C10 alkoxys, and C6 to C12 aryloxys;
n is 1 or 2 in a particular embodiment; and
T is a bridging group selected from the group consisting of C1 to C10 alkylenes, C6 to C12 arylenes and C1 to C10 heteroatom containing groups, and C6 to C12 heterocyclic groups; wherein each T group bridges adjacent xe2x80x9cCpAM(Q2GZ)Xnxe2x80x9d groups, and is chemically bonded to the CpA groups.
m is an integer from 1 to 7; m is an integer from 2 to 6 in a more particular embodiment.
In another aspect of the invention, the at least one metallocene catalyst component can be described more particularly in structures (Va), (Vb), (Vc) and (Vd): 
wherein in structures (Va) to (Vd) M is selected from the group consisting of
Group 3 to Group 12 atoms, and selected from the group consisting of Group 3 to Group 10 atoms in a more particular embodiment, and selected from the group consisting of Group 3 to Group 6 atoms in yet a more particular embodiment, and selected from the group consisting of Group 4 atoms in yet a more particular embodiment, and selected from the group consisting of Zr and Hf in yet a more particular embodiment; and is Zr in yet a more particular embodiment;
wherein Q in (Va-i) and (Va-ii) is selected from the group consisting of halogen ions, alkyls, alkylenes, aryls, arylenes, alkoxys, aryloxys, amines, alkylamines, phosphines, alkylphosphines, substituted alkyls, substituted aryls, substituted alkoxys, substituted aryloxys, substituted amines, substituted alkylamines, substituted phosphines, substituted alkylphosphines, carbamates, heteroallyls, carboxylates (non-limiting examples of suitable carbamates and carboxylates include trimethylacetate, trimethylacetate, methylacetate, p-toluate, benzoate, diethylcarbamate, and dimethylcarbamate), fluorinated alkyls, fluorinated aryls, and fluorinated alkylcarboxylates;
q is an integer ranging from 1 to 3;
wherein each R* is independently: selected from the group consisting of hydrocarbyls and heteroatom-containing hydrocarbyls in one embodiment; and selected from the group consisting of alkylenes, substituted alkylenes and heteroatom-containing hydrocarbyls in another embodiment; and selected from the group consisting of C1 to C12 alkylenes, C1 to C12 substituted alkylenes, and C1 to C12 heteroatom-containing hydrocarbons in a more particular embodiment; and selected from the group consisting of C1 to C4 alkylenes in yet a more particular embodiment; and wherein both R* groups are identical in another embodiment in structures (Vb-d);
A is as described above for (A) in structure (II), and more particularly, selected from the group consisting of xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SO2xe2x80x94, xe2x80x94NRxe2x80x94, xe2x95x90SiR2, xe2x95x90GeR2, xe2x95x90SnR2, xe2x80x94R2SiSiR2xe2x80x94, RPxe2x95x90, C1 to C12 alkylenes, substituted C1 to C12 alkylenes, divalent C4 to C12 cyclic hydrocarbons and substituted and unsubstituted aryl groups in one embodiment; and selected from the group consisting of C5 to C8 cyclic hydrocarbons, xe2x80x94CH2CH2xe2x80x94, xe2x95x90CR2 and xe2x95x90SiR2 in a more particular embodiment; wherein and R is selected from the group consisting of alkyls, cycloalkyls, aryls, alkoxys, fluoroalkyls and heteroatom-containing hydrocarbons in one embodiment; and R is selected from the group consisting of C1 to C6 alkyls, substituted phenyls, phenyl, and C1 to C6 alkoxys in a more particular embodiment; and R is selected from the group consisting of methoxy, methyl, phenoxy, and phenyl in yet a more particular embodiment;
wherein A may be absent in yet another embodiment, in which case each R* is defined as for R1-R12;
each X is as described above in (I);
n is an integer from 0 to 4, and from 1 to 3 in another embodiment, and 1 or 2 in yet another embodiment; and
R1 through R12 are independently: selected from the group consisting of hydrogen radical, halogen radicals, C1 to C12 alkyls, C2 to C12 alkenyls, C6 to C12 aryls, C7 to C20 alkylaryls, C1 to C12 alkoxys, C1 to C12 fluoroalkyls, C6 to C12 fluoroaryls, and C1 to C12 heteroatom-containing hydrocarbons and substituted derivatives thereof in one embodiment; selected from the group consisting of hydrogen radical, fluorine radical, chlorine radical, bromine radical, C1 to C6 alkyls, C2 to C6 alkenyls, C7 to C18 alkylaryls, C1 to C6 fluoroalkyls, C2 to C6 fluoroalkenyls, C7 to C18 fluoroalkylaryls in a more particular embodiment; and hydrogen radical, fluorine radical, chlorine radical, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, hexyl, phenyl, 2,6-di-methylpheyl, and 4-tertiarybutylpheyl groups in yet a more particular embodiment; wherein adjacent R groups may form a ring, either saturated, partially saturated, or completely saturated.
The structure of the metallocene catalyst component represented by (Va) may take on many forms such as disclosed in, for example, U.S. Pat. Nos. 5,026,798, 5,703,187, and 5,747,406, including a dimer or oligomeric structure, such as disclosed in, for example, U.S. Pat. Nos. 5,026,798 and 6,069,213.
In a particular embodiment of the metallocene represented in (Vd), R1 and R2 form a conjugated 6-membered carbon ring system that may or may not be substituted.
Non-limiting examples of metallocene catalyst components consistent with the description herein include:
cyclopentadienylzirconium Xn,
indenylzirconium Xn,
(1-methylindenyl)zirconium Xn,
(2-methylindenyl)zirconium Xn,
(1-propylindenyl)zirconium Xn,
(2-propylindenyl)zirconium Xn,
(1-butylindenyl)zirconium Xn,
(2-butylindenyl)zirconium Xn,
(methylcyclopentadienyl)zirconium Xn,
tetrahydroindenylzirconium Xn,
(pentamethylcyclopentadienyl)zirconium Xn,
cyclopentadienylzirconium Xn,
pentamethylcyclopentadienyltitanium Xn,
tetramethylcyclopentyltitanium Xn,
1,2,4-trimethylcyclopentadienylzirconium Xn,
dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(cyclopentadienyl)zirconium Xn,
dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2,3-trimethylcyclopentadienyl)zirconium Xn,
dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2-dimethylcyclopentadienyl)zirconium Xn,
dimethylsilyl(1,2,3,4-tetramethyl-cyclopentadienyl)(2-methylcyclopentadienyl)zirconium Xn,
dimethylsilyl(cyclopentadienyl)(indenyl)zirconium Xn,
dimethylsilyl(2-methylindenyl)(fluorenyl)zirconium Xn,
diphenylsilyl(1,2,3,4-tetramethyl-cyclopentadienyl)(3-propylcyclopentadienyl)zirconium Xn,
dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl) (3-t-butylcyclopentadienyl)zirconium Xn,
dimethylgermyl(1,2-dimethylcyclopentadienyl)(3-isopropylcyclopentadienyl)zirconium Xn,
dimethylsilyl(1,2,3,4-tetramethyl-cyclopentadienyl)(3-methylcyclopentadienyl) zirconium Xn,
diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium Xn,
diphenylmethylidene(cyclopentadienyl)(indenyl)zirconium Xn,
iso-propylidenebis(cyclopentadienyl)zirconium Xn,
iso-propylidene(cyclopentadienyl)(9-fluorenyl)zirconium Xn,
iso-propylidene(3-methylcyclopentadienyl)(9-fluorenyl)zirconium Xn,
ethylenebis(9-fluorenyl)zirconium Xn,
meso-ethylenebis(1-indenyl)zirconium Xn,
ethylenebis(1-indenyl)zirconium Xn,
ethylenebis(2-methyl-1-indenyl)zirconium Xn,
ethylenebis(2-methyl-4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
ethylenebis(2-propyl-4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
ethylenebis(2-isopropyl-4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
ethylenebis(2-butyl-4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
ethylenebis(2-isobutyl-4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
dimethylsilyl(4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
diphenyl(4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium Xn,
dimethylsilylbis(cyclopentadienyl)zirconium Xn,
dimethylsilylbis(9-fluorenyl)zirconium Xn,
dimethylsilylbis(1-indenyl)zirconium Xn,
dimethylsilylbis(2-methylindenyl)zirconium Xn,
dimethylsilylbis(2-propylindenyl)zirconium Xn,
dimethylsilylbis(2-butylindenyl)zirconium Xn,
diphenylsilylbis(2-methylindenyl)zirconium Xn,
diphenylsilylbis(2-propylindenyl)zirconium Xn,
diphenylsilylbis(2-butylindenyl)zirconium Xn,
dimethylgermylbis(2-methylindenyl)zirconium Xn,
dimethylsilylbis(tetrahydroindenyl)zirconium Xn,
dimethylsilylbis(tetramethylcyclopentadienyl)zirconium Xn,
dimethylsilyl(cyclopentadienyl)(9-fluorenyl)zirconium Xn,
diphenylsilyl(cyclopentadienyl)(9-fluorenyl)zirconium Xn,
diphenylsilylbis(indenyl)zirconium Xn,
cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(cyclopentadienyl)zirconium Xn,
cyclotetramethylenesilyl(tetramethylcyclopentadienyl)(cyclopentadienyl) zirconium Xn,
cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2-methylindenyl)zirconium Xn,
cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(3-methylcyclopentadienyl)zirconium Xn,
cyclotrimethylenesilylbis(2-methylindenyl)zirconium Xn,
cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2,3,5-trimethylcyclopentadienyl)zirconium Xn,
cyclotrimethylenesilylbis(tetramethylcyclopentadienyl)zirconium Xn,
dimethylsilyl(tetramethylcyclopentadieneyl)(N-tert-butylamido)titanium Xn,
bis(cyclopentadienyl)chromium Xn,
bis(cyclopentadienyl)zirconium Xn,
bis(n-butylcyclopentadienyl)zirconium Xn,
bis(n-dodecyclcyclopentadienyl)zirconium Xn,
bis(ethylcyclopentadienyl)zirconium Xn,
bis(iso-butylcyclopentadienyl)zirconium Xn,
bis(iso-propylcyclopentadienyl)zirconium Xn,
bis(methylcyclopentadienyl)zirconium Xn,
bis(n-oxtylcyclopentadienyl)zirconium Xn,
bis(n-pentylcyclopentadienyl)zirconium Xn,
bis(n-propylcyclopentadienyl)zirconium Xn,
bis(trimethylsilylcyclopentadienyl)zirconium Xn,
bis(1,3-bis(trimethylsilyl)cyclopentadienyl)zirconium Xn,
bis(1-ethyl-2-methylcyclopentadienyl)zirconium Xn,
bis(1-ethyl-3-methylcyclopentadienyl)zirconium Xn,
bis(pentamethylcyclopentadienyl)zirconium Xn,
bis(pentamethylcyclopentadienyl)zirconium Xn,
bis(1-propyl-3-methylcyclopentadienyl)zirconium Xn,
bis(1-n-butyl-3-methylcyclopentadienyl)zirconium Xn,
bis(1-isobutyl-3-methylcyclopentadienyl)zirconium Xn,
bis(1-propyl-3-butylcyclopentadienyl)zirconium Xn,
bis(1,3-n-butylcyclopentadienyl)zirconium Xn,
bis(4,7-dimethylindenyl)zirconium Xn,
bis(indenyl)zirconium Xn,
bis(2-methylindenyl)zirconium Xn,
cyclopentadienylindenylzirconium Xn,
bis(n-propylcyclopentadienyl)hafnium Xn,
bis(n-butylcyclopentadienyl)hafnium Xn,
bis(n-pentylcyclopentadienyl)hafnium Xn,
(n-propyl cyclopentadienyl)(n-butyl cyclopentadienyl)hafnium Xn,
bis[(2-trimethylsilylethyl)cyclopentadienyl]hafnium Xn,
bis(trimethylsilyl cyclopentadienyl)hafnium Xn,
bis(2-n-propylindenyl)hafnium Xn,
bis(2-n-butylindenyl)hafnium Xn,
dimethylsilylbis(n-propylcyclopentadienyl)hafnium Xn,
dimethylsilylbis(n-butylcyclopentadienyl)hafnium Xn,
bis(9-n-propylfluorenyl)hafnium Xn,
bis(9-n-butylfluorenyl)hafnium Xn,
(9-n-propylfluorenyl)(2-n-propylindenyl)hafnium Xn,
bis(1-n-propyl-2-methylcyclopentadienyl)hafnium Xn,
(n-propylcyclopentadienyl)(1-n-propyl-3-n-butylcyclopentadienyl)hafnium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido)titanium Xn,
dimethylsilyl(tetramethyleyclopentadienyl)(cyclobutylamido)titanium Xn,
dimethylsilyl(tetramethyleyclopentadienyl)(cyclopentylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titanium Xn,
dimethylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclobutylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclopentylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium, Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titanium Xn,
methylphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclobutylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclopentylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titanium Xn,
diphenylsilyl(tetramethyleyclopentadienyl)(n-octylamido)titanium Xn,
diphenylsilyl(tetramethyleyclopentadienyl)(n-decylamido)titanium Xn,
diphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titanium Xn, and derivatives thereof.
By xe2x80x9cderivatives thereofxe2x80x9d, it is meant any substitution or ring formation as described above for structures (Va-d) in one embodiment; and in particular, replacement of the metal xe2x80x9cMxe2x80x9d (Cr, Zr, Ti or Hf) with an atom selected from the group consisting of Cr, Zr, Hf and Ti; and replacement of the xe2x80x9cXxe2x80x9d group with any of C1 to C5 alkyls, C6 aryls, C6 to C10 alkylaryls, fluorine or chlorine; n is 1, 2 or 3. In a particular embodiment, each of the above metallocenes is a fluorided metallocene wherein one or more of the X groups is a fluoride; and all X groups are fluorides in yet a more particular embodiment.
It is contemplated that the metallocene catalysts components described above include their structural or optical or enantiomeric isomers (racemic mixture), and may be a pure enantiomer in one embodiment.
As used herein, a single, bridged, asymmetrically substituted metallocene catalyst component having a racemic and/or meso isomer does not, itself, constitute at least two different bridged, metallocene catalyst components.
The xe2x80x9cmetallocene catalyst componentxe2x80x9d useful in the present invention may comprise any combination of any xe2x80x9cembodimentxe2x80x9d described herein.
When combined to form the bimetallic catalyst component, the molar ratio of metal from the first catalyst component to the second catalyst component (e.g., molar ratio of Ti:Zr) is a value of from 0.1 to 20 in one embodiment; and from 1 to 18 in another embodiment, and from 2 to 15 in yet another embodiment, and from 3 to 12 in yet another embodiment; and from 4 to 10 in yet another embodiment, and from 4 to 8 in yet another embodiment; wherein a desirable molar ratio of first catalyst component metal:second catalyst component metal is any combination of any upper limit with any lower limit described herein.
Activator
As used herein, the term xe2x80x9cactivatorxe2x80x9d is defined to be any compound or combination of compounds, supported or unsupported, which can activate a catalyst compound (e.g., Ziegler-Natta, metallocenes, Group 15-containing catalysts, etc.), such as by creating a cationic species from the catalyst component. Typically, this involves the abstraction of at least one leaving group (X group in the formulas/structures above) from the metal center of the catalyst component. The catalyst components of the present invention are thus activated towards olefin polymerization using such activators. Embodiments of such activators include Lewis acids such as cyclic or oligomeric poly(hydrocarbylaluminum oxides), alkylaluminum compounds and so called non-coordinating ionic activators (xe2x80x9cNCAxe2x80x9d) (alternately, xe2x80x9cionizing activatorsxe2x80x9d or xe2x80x9cstoichiometric activatorsxe2x80x9d), or any other compound that can convert a neutral metallocene catalyst component to a metallocene cation that is active with respect to olefin polymerization.
More particularly, it is within the scope of this invention to use Lewis acids such as alumoxane (e.g., xe2x80x9cMAOxe2x80x9d), modified alumoxane (e.g., xe2x80x9cTIBAOxe2x80x9d), and alkylaluminum compounds as activators, and/or ionizing activators (neutral or ionic) such as tri (n-butyl)ammonium tetrakis(pentafluorophenyl)boron and/or a trisperfluorophenyl boron metalloid precursors to activate desirable metallocenes described herein. MAO and other aluminum-based activators are well known in the art. Ionizing activators are well known in the art and are described by, for example, Eugene You-Xian Chen and Tobin J. Marks, Cocatalysts for Metal-Catalyzed Olefin Polymerization: Activators, Activation Processes, and Structure-Activity Relationships 100(4) Chemical Reviews 1391-1434 (2000). The activators may be associated with or bound to a support, either in association with the catalyst component (e.g., metallocene) or separate from the catalyst component, such as described by Gregory G. Hlatky, Heterogeneous Single-Site Catalysts for Olefin Polymerization 100(4) Chemical Reviews 1347-1374 (2000).
Non-limiting examples of aluminum alkyl compounds which may be utilized as activators for the catalyst precursor compounds for use in the methods of the present invention include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum and the like.
Examples of neutral ionizing activators include Group 13 tri-substituted compounds, in particular, tri-substituted boron, tellurium, aluminum, gallium and indium compounds, and mixtures thereof. The three substituent groups are each independently selected from the group consisting of alkyls, alkenyls, halogen, substituted alkyls, aryls, arylhalides, alkoxy and halides. In one embodiment, the three groups are independently selected from the group consisting of halogen, mono or multicyclic (including halosubstituted) aryls, alkyls, and alkenyl compounds and mixtures thereof. In another embodiment, the three groups are selected from the group consisting of alkenyl groups having 1 to 20 carbon atoms, alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms and aryl groups having 3 to 20 carbon atoms (including substituted aryls), and combinations thereof. In yet another embodiment, the three groups are selected from the group consisting of alkyls having 1 to 4 carbon groups, phenyl, naphthyl and mixtures thereof. In yet another embodiment, the three groups are selected from the group consisting of highly halogenated alkyls having 1 to 4 carbon groups, highly halogenated phenyls, and highly halogenated naphthyls and mixtures thereof By xe2x80x9chighly halogenatedxe2x80x9d, it is meant that at least 50% of the hydrogens are replaced by a halogen group selected from the group consisting of fluorine, chlorine and bromine. In yet another embodiment, the neutral stoichiometric activator is a tri-substituted Group 13 compound comprising highly fluorided aryl groups, the groups being highly fluorided phenyl and highly fluorided naphthyl groups.
In another embodiment, the neutral tri-substituted Group 13 compounds are boron compounds such as a trisperfluorophenyl boron, trisperfluoronaphthyl boron, tris(3,5-di(trifluoromethyl)phenyl)boron, tris(di-t-butylmethylsilyl)perfluorophenylboron, and other highly fluorinated trisarylboron compounds and combinations thereof, and their aluminum equivalents. Other suitable neutral ionizing activators are described in U.S. Pat. Nos. 6,399,532 B1, 6,268,445 B1, and in 19 Organometallics 3332-3337 (2000), and in 17 Organometallics 3996-4003 (1998).
Illustrative, not limiting examples of ionic ionizing activators include trialkyl-substituted ammonium salts such as triethylammonium tetra(phenyl)boron, tripropylammonium tetra(phenyl)boron, tri(n-butyl)ammonium tetra(phenyl)boron, trimethylammonium tetra(p-tolyl)boron, trimethylammonium tetra(o-tolyl)boron, tributylammonium tetra(pentafluorophenyl)boron, tripropylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(m,m-dimethylphenyl)boron, tributylammonium tetra(p-tri-fluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, tri(n-butyl)ammonium tetra(o-tolyl)boron and the like; N,N-dialkyl anilinium salts such as N,N-dimethylanilinium tetra(phenyl)boron, N,N-diethylanilinium tetra(phenyl)boron, N,N-2,4,6-pentamethylanilinium tetra(phenyl)boron and the like; dialkyl ammonium salts such as di-(isopropyl)ammonium tetra(pentafluorophenyl)boron, dicyclohexylammonium tetra(phenyl)boron and the like; and triaryl phosphonium salts such as triphenylphosphonium tetra(phenyl)boron, tri(methylphenyl)phosphonium tetra(phenyl)boron, tri(dimethylphenyl)phosphonium tetra(phenyl)boron and the like, and their aluminum equivalents.
In yet another embodiment of the activator of the invention, an alkylaluminum can be used in conjunction with a heterocyclic compound. The ring of the heterocyclic compound may includes at least one nitrogen, oxygen, and/or sulfur atom, and includes at least one nitrogen atom in one embodiment. The heterocyclic compound includes 4 or more ring members in one embodiment, and 5 or more ring members in another embodiment.
The heterocyclic compound for use as an activator with an alkylaluminum may be unsubstituted or substituted with one or a combination of substituent groups. Examples of suitable substituents include halogen, alkyl, alkenyl or alkynyl radicals, cycloalkyl radicals, aryl radicals, aryl substituted alkyl radicals, acyl radicals, aroyl radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- or dialkyl- carbamoyl radicals, acyloxy radicals, acylamino radicals, aroylamino radicals, straight, branched or cyclic, alkylene radicals, or any combination thereof. The substituents groups may also be substituted with halogens, particularly fluorine or bromine, or heteroatoms or the like.
Non-limiting examples of hydrocarbon substituents include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl or phenyl groups and the like, including all their isomers, for example tertiary butyl, isopropyl, and the like. Other examples of substituents include fluoromethyl, fluoroethyl, difluoroethyl, iodopropyl, bromohexyl or chlorobenzyl.
In one embodiment, the heterocyclic compound is unsubstituted. In another embodiment one or more positions on the heterocyclic compound are substituted with a halogen atom or a halogen atom containing group, for example a halogenated aryl group. In one embodiment the halogen is selected from the group consisting of chlorine, bromine and fluorine, and selected from the group consisting of fluorine and bromine in another embodiment, and the halogen is fluorine in yet another embodiment.
Non-limiting examples of heterocyclic compounds utilized in the activator of the invention include substituted and unsubstituted pyrroles, imidazoles, pyrazoles, pyrrolines, pyrrolidines, purines, carbazoles, and indoles, phenyl indoles, 2,5, -dimethylpyrroles, 3-pentafluorophenylpyrrole, 4,5,6,7-tetrafluoroindole or 3,4-difluoropyrroles.
In one embodiment, the heterocyclic compound described above is combined with an alkyl aluminum or an alumoxane to yield an activator compound which, upon reaction with a catalyst component, for example a metallocene, produces an active polymerization catalyst. Non-limiting examples of alkylaluminums include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tri-iso-octylaluminum, triphenylaluminum, and combinations thereof.
Other activators include those described in WO 98/07515 such as tris (2,2xe2x80x2,2xe2x80x3-nonafluorobiphenyl) fluoroaluminate. Combinations of activators are also contemplated by the invention, for example, alumoxanes and ionizing activators in combinations. Other activators include aluminum/boron complexes, perchlorates, periodates and iodates including their hydrates; lithium (2,2xe2x80x2-bisphenyl-ditrimethylsilicate)4THF; silylium salts in combination with a non-coordinating compatible anion. Also, methods of activation such as using radiation, electro-chemical oxidation, and the like are also contemplated as activating methods for the purposes of rendering the neutral bulky ligand metallocene-type catalyst compound or precursor to a bulky ligand metallocene-type cation capable of polymerizing olefins. Other activators or methods for activating a bulky ligand metallocene-type catalyst compound are described in for example, U.S. Pat. Nos. 5,849,852, 5,859,653 and 5,869,723 and WO 98/32775.
In general, the activator and catalyst component(s) are combined in mole ratios of activator to catalyst component from 1000:1 to 0.1:1 in one embodiment, and from 300:1 to 1:1 in a more particular embodiment, and from 150:1 to 1:1 in yet a more particular embodiment, and from 50:1 to 1:1 in yet a more particular embodiment, and from 10:1 to 0.5:1 in yet a more particular embodiment, and from 3:1 to 0.3:1 in yet a more particular embodiment, wherein a desirable range may include any combination of any upper mole ratio limit with any lower mole ratio limit described herein. When the activator is a cyclic or oligomeric poly(hydrocarbylaluminum oxide) (e.g., xe2x80x9cMAOxe2x80x9d), the mole ratio of activator to catalyst component ranges from 2:1 to 100,000:1 in one embodiment, and from 10:1 to 10,000:1 in another embodiment, and from 50:1 to 2,000:1 in a more particular embodiment. When the activator is a neutral or ionic ionizing activator such as a boron alkyl and the ionic salt of a boron alkyl, the mole ratio of activator to catalyst component ranges from 0.5:1 to 10:1 in one embodiment, and from 1:1 to 5:1 in yet a more particular embodiment.
More particularly, the molar ratio of Al/metallocene-metal (Al from MAO) ranges from 40 to 500 in one embodiment; and ranges from 50 to 400 in another embodiment; and ranges from 60 to 300 in yet another embodiment, and ranges from 70 to 200 in yet another embodiment; and ranges from 80 to 175 in yet another embodiment; and ranges from 90 to 125 in yet another embodiment, wherein a desirable molar ratio of Al(MAO) to metallocene-metal xe2x80x9cMxe2x80x9d can be any combination of any upper limit with any lower limit described herein.
Supports
A support may also be present as part of the bimetallic catalyst system of the invention. Supports, methods of supporting, modifying, and activating supports for single-site catalyst such as metallocenes is discussed in, for example, 1 Metallocene-Based Polyolefins 173-218 (J. Scheirs and W. Kaminsky eds., John Wiley and Sons, Ltd. 2000). The terms xe2x80x9csupportxe2x80x9d or xe2x80x9ccarrierxe2x80x9d, as used herein, are used interchangeably and refer to any support material, a porous support material in one embodiment, including inorganic or organic support materials. Non-limiting examples of support materials include inorganic oxides and inorganic chlorides, and in particular such materials as talc, clay, silica, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminum phosphate gel, glass beads, and polymers such as polyvinylchloride and substituted polystyrene, functionalized or crosslinked organic supports such as polystyrene divinyl benzene polyolefins or polymeric compounds, and mixtures thereof, and graphite, in any of its various forms.
The support may be contacted with the other components of the catalyst system in any number of ways. In one embodiment, the support is contacted with the activator to form an association between the activator and support, or a xe2x80x9cbound activatorxe2x80x9d. In another embodiment, the catalyst component may be contacted with the support to form a xe2x80x9cbound catalyst componentxe2x80x9d. In yet another embodiment, the support may be contacted with the activator and catalyst component together, or with each partially in any order. The components may be contacted by any suitable means as in a solution, slurry, or solid form, or some combination thereof, and may be heated to any desirable temperature to effectuate a desirable chemical/physical transformation.
Desirable carriers are inorganic oxides that include Group 2, 3, 4, 5, 13 and 14 oxides and chlorides in one embodiment, and more particularly, inorganic oxides and chlorides of Group 13 and 14 atoms. Yet more particularly, support materials include silica, alumina, silica-alumina, magnesium chloride, graphite, and mixtures thereof. Other useful supports include magnesia, titania, zirconia, montmorillonite (EP 0 511 665 B1), phyllosilicate, and the like. Also, combinations of these support materials may be used, for example, silica-chromium, silica-alumina, silica-titania and the like. Additional support materials may include those porous acrylic polymers described in EP 0 767 184 B1.
In one aspect of the support useful in the invention, the support possess a surface area in the range of from 10 to 700 m2/g, pore volume in the range of from 0.1 to 4.0 cm3/g and average particle size in the range of from 5 to 500 xcexcm. In another embodiment, the surface area of the carrier is in the range of from 50 to 500 m2/g, pore volume of from 0.5 to 3.5 cm3/g and average particle size of from 10 to 200 xcexcm. In yet another embodiment, the surface area of the carrier is in the range is from 100 to 400 m2/g, pore volume from 0.8 to 3.0 cm3/g and average particle size is from 5 to 100 xcexcm. The average pore size of the carrier of the invention typically has pore size in the range of from 10 to 1000 xc3x85, from 50 to 500 xc3x85 in another embodiment, and from 75 to 350 xc3x85 in yet another embodiment.
In one embodiment of the support, graphite is used as the support. The graphite is a powder in one embodiment. In another embodiment, the graphite is flake graphite. In another embodiment, the graphite and has a particle size of from 1 to 500 microns, from 1 to 400 microns in another embodiment, and from 1 to 200 in yet another embodiment, and from 1 to 100 microns in yet another embodiment.
Dehydration or calcining of the support may or may also be carried out. In one embodiment, the support is calcined prior to reaction with the fluorine or other support-modifying compound. In another embodiment, the support is calcined and used without further modification, or calcined, followed by contacting with one or more activators and/or catalyst components. Suitable calcining temperatures range from 100xc2x0 C. to 1500xc2x0 C. in one embodiment, and from 200xc2x0 C. to 1200xc2x0 C. in another embodiment, and from 300xc2x0 C. to 1000xc2x0 C. in another embodiment, and from 350xc2x0 C. to 900xc2x0 C. in yet another embodiment, and from 400xc2x0 C. to 850xc2x0 C. in yet a more particular embodiment, and from 800xc2x0 C. to 900xc2x0 C. in yet a more particular embodiment, and from 810xc2x0 C. to 890xc2x0 C. in yet a more particular embodiment, wherein a desirable range comprises any combination of any upper temperature limit with any lower temperature limit. Calcining may take place in the absence of oxygen and moisture by using, for example, an atmosphere of dry nitrogen.
The support, especially an inorganic support or graphite support, may be pretreated such as by a halogenation process or other suitable process that, for example, associates a chemical species with the support either through chemical bonding, ionic interactions, or other physical or chemical interaction. In one embodiment, the support is fluorided. The fluorine compounds suitable for providing fluorine for the support are desirably inorganic fluorine containing compounds. Such inorganic fluorine containing compounds may be any compound containing a fluorine atom as long as it does not contain a carbon atom. Particularly desirable are inorganic fluorine containing compounds selected from the group consisting of NH4BF4, (NH4)2SiF6, NH4PF6, NH4F, (NH4)2TaF7, NH4NbF4, (NH4)2GeF6, (NH4)2SmF6, (NH4)2TiF6, (NH4)2ZrF6, MoF6, ReF6, GaF3, SO2ClF, F2, SiF4, SF6, ClF3, ClF5, BrF5, IF7, NF3, HF, BF3, NHF2 and NH4HF2.
A desirable method of treating the support with the fluorine compound is to dry mix the two components by blending at a concentration of from 0.01 to 10.0 millimole F/g of support in one embodiment, and in the range of from 0.05 to 6.0 millimole F/g of support in another embodiment, and in the range of from 0.1 to 3.0 millimole F/g of support in yet another embodiment. The fluorine compound can be dry mixed with the support either before or after charging to the vessel for dehydration or calcining the support. Accordingly, the fluorine concentration present on the support is in the range of from 0.2 to 5 wt % in one embodiment, and from 0.6 to 3.5 wt % of support in another embodiment.
Another method of treating the support with the fluorine compound is to dissolve the fluorine in a solvent, such as water, and then contact the support with the fluorine containing solution. When water is used and silica is the support, it is desirable to use a quantity of water that is less than the total pore volume of the support. Desirably, the support and, for example, fluorine compounds are contacted by any suitable means such as by dry mixing or slurry mixing at a temperature of from 100xc2x0 C. to 1000xc2x0 C. in one embodiment, and from 200xc2x0 C. to 800xc2x0 C. in another embodiment, and from 300xc2x0 C. to 600xc2x0 C. in yet another embodiment, the contacting in any case taking place for between two to eight hours.
It is within the scope of the present invention to co-contact (or xe2x80x9cco-immobilizexe2x80x9d) more than one catalyst component with a support. Non-limiting examples of co-immobilization of catalyst components include two or more of the same or different metallocene catalyst components, one or more metallocene with a Ziegler-Natta type catalyst, one or more metallocene with a chromium or xe2x80x9cPhillipsxe2x80x9d type catalyst, one or more metallocenes with a Group 15 containing catalyst, and any of these combinations with one or more activators. More particularly, co-supported combinations include metallocene A/metallocene A; metallocene A/metallocene B; metallocene/Ziegler Natta; metallocene/Group 15 containing catalyst; metallocene/chromium catalyst; metallocene/Ziegler Natta/Group 15-containing catalyst; metallocene/chromium catalyst/Group 15 containing catalyst, any of the these with an activator, and combinations thereof.
Further, the catalyst system of the present invention can include any combination of activators and catalyst components, either supported or not supported, in any number of ways. For example, the catalyst component may include any one or both of metallocenes and/or Group 15-containing catalysts components (e.g., U.S. Pat. Nos. 6,265,505; 5,707,913; EP 0 893 454; and WO 99/01460), and may include any combination of activators, any of which may be supported by any number of supports as described herein. Non-limiting examples of catalyst system combinations useful in the present invention include MN+NCA; MN:S+NCA; NCA:S+MN; MN:NCA:S; MN+AlA; MN:S+AlA; AlA:S+MN; MN:AlA:S; AlA:S+NCA+MN; NCA:S+MN+AlA; G15+NCA; G15:S+NCA; NCA:S+G15; G15:NCA:S; G15+AlA; G15:S+AlA; AlA:S+G15; G15:AlA:S; AlA:S+NCA+G15; NCA:S+G15+AlA; MN+NCA+G15; MN:S+NCA+G15; NCA:S+MN+G15; MN:NCA:S+G15; MN+G15+AlA; MN:S+AlA+G15; AlA:S+MN+G15; MN:AlA:S+G15; AlA:S+NCA+MN+G15; NCA:S+MN+AlA+G15; MN+NCA; G15:MN:S+NCA; G15:NCA:S+MN; G15:MN:NCA:S; G15:MN:S+AlA; G15:AlA:S+MN; G15:MN:AlA:S; G15:AlA:S+NCA+MN; G15:NCA:S+MN+AlA; MN+ZN+NCA; MN:S+ZN+NCA; NCA:S+ZN+MN; ZN:MN:NCA:S; MN+ZN+AlA; MN:ZN:S+AlA; AlA:S+ZN+MN; MN:AlA:ZN:S; AlA:ZN:S+NCA+MN; MN:AlA:S+ZN; wherein xe2x80x9cMNxe2x80x9d is metallocene component, xe2x80x9cZNxe2x80x9d is a Ziegler-Natta catalyst component, such as described above for the first catalyst component, xe2x80x9cNCAxe2x80x9d is a non-coordinating activator including ionic and neutral boron and aluminum based compounds as described above, xe2x80x9cAlAxe2x80x9d is an aluminum alkyl and/or alumoxane based activator, xe2x80x9cG15xe2x80x9d is a Group 15-containing catalyst component as described above, and xe2x80x9cSxe2x80x9d is a support; and wherein the use of xe2x80x9c:xe2x80x9d with xe2x80x9cSxe2x80x9d means that that those groups next to the colon are associated with (xe2x80x9csupported byxe2x80x9d) the support as by pretreatment and other techniques known in the art, and the xe2x80x9c+xe2x80x9d sign means that the additional component is not directly bound to the support but present with the support and species bound to the support, such as present in a slurry, solution, gas phase, or another way, but is not meant to be limited to species that have no physico-chemical interaction with the support and/or supported species. Thus, for example, the embodiment xe2x80x9cMN:NCA:S+G15xe2x80x9d means that a metallocene and NCA activator are bound to a support, and present in, for example, a gas phase polymerization with a Group 15 containing catalyst component.
In a particular embodiment, the catalyst system is selected from the group consisting of MN:ZN:NCA:S; MN:ZN:AlA:S; MN:AlA:S+ZN; ZN:AlA:S+MN; MN:NCA:S+ZN; and ZN:MN:AlA:NCA:S. The components may be combined in any order desirable to achieve the highest polymerization activity. In one embodiment, the ZN catalyst is immobilized prior to immobilizing the metallocene; in another embodiment, the metallocene is first immobilized, and in yet another embodiment, an activator is first immobilized, followed by either the metallocene and/or the ZN catalyst. In yet another embodiment, both the MN and ZN catalyst components are immobilized simultaneously on the support, the support being pretreated with activator in one embodiment, and treated after catalyst component treatment in yet another embodiment.
One embodiment of the support useful in the present invention is a so called xe2x80x9cenhanced supportxe2x80x9d, prepared by heating support particles at a dehydration temperature of at least 800xc2x0 C. or more, and between 800xc2x0 C. and 1000xc2x0 C. in another embodiment, resulting in an enhanced support having a modified chemical structure. In a particular embodiment, the heating of the support takes place in an inert (e.g., N2 or Ar) atmosphere, and in the absence of water. In preferred embodiments, increased productivity is achieved when the enhanced support is combined with the other parts of the bimetallic catalyst discussed herein, to form a supported bimetallic catalyst, which is then contacted with monomers during polymerization to produce a bimodal polyolefin compositions.
In one or more specific embodiments, an enhanced support is first prepared, preferably in the manner described below; then that enhanced support is treated (e.g., combined with ingredients that form the first catalyst) to provide a supported catalyst that includes the first catalyst component. In specific embodiments, that supported first catalyst is then treated in the presence of the second catalyst component to provide a supported bimetallic catalyst.
The enhanced support is prepared by any suitable means, and more particularly, by any means wherein water is removed from the support, such as by heating, exposure to low pressure, chemical treatment, or combinations thereof. Heating the support at a dehydration temperature of at least 800xc2x0 C., and between 800xc2x0 C. and 1000xc2x0 C. in a particular embodiment, provides an enhanced support, for example, enhanced silica, which provides surprisingly improved results over support that is dehydrated at lower temperatures, that is, below 800xc2x0 C., even slightly lower temperatures, for example, 760xc2x0 C. While not immediately apparent from the enhancement procedure itself, it is contemplated that the heat treatment results in an actual chemical and/or physical change in the support structure itself, which only reveals its beneficial structure when combined with a first and second catalyst components described herein, and placed in the context of an actual polymerization. For example, when the enhanced silica is combined with both the first catalyst component and the second catalyst component to form a supported bimetallic catalyst composition, that supported bimetallic catalyst composition, including the enhanced silica, has been discovered as having desirably high productivity when used in a polymerization process for making bimodal polyolefin in a single reactor. For example, a productivity of at least 3000 grams polymer/gram catalyst can be achieved. More preferably, the bimetallic catalyst that includes the enhanced support has a productivity of at least 3500 grams polymer/gram catalyst. Even more preferably yet, a bimetallic catalyst having the enhanced support has a productivity of at least 4000 grams polymer/gram catalyst. Other specific embodiments of the invention include bimetallic catalysts with productivities of 4500 grams polymer/gram catalyst and above, 5000 grams polymer/gram catalyst and above, or even 6000 grams polymer/gram catalyst and above.
In a particular embodiment, the support useful in the present invention is a Group 13 or 14 inorganic oxide support having a pore volume ranging from 0.8 to 3 cm3/g and a surface area of from 100 to 500 m2/g. This support is desirably dehydrated as described herein in one embodiment. A preferred support is an amorphous high surface area silica, such as Davison 952 or Sylopol(copyright) 955, sold by Davison Chemical Division of W.R. Grace and Company. Those silicas are in spherical form, prepared by the spray drying process, with a surface area of 300 m2/g and a pore volume of 1.65 cm3/g. A procedure for dehydrating the silica at 600xc2x0 C. is set forth in U.S. Pat. No. 5,525,678.
The enhanced support may be combined with a non-polar hydrocarbon diluent to form a support slurry, which can be stirred and optionally heated during mixing.
A variety of non-polar hydrocarbon diluents can be used to form the support slurry, but any non-polar hydrocarbon selected should remain in liquid form at all relevant reaction temperatures, and the ingredients used to form the first catalyst component should be at least partially soluble in the non-polar hydrocarbon. Accordingly, the non-polar hydrocarbon diluent is considered to be a xe2x80x9csolventxe2x80x9d herein, even though in certain embodiments the ingredients are only partially soluble in the hydrocarbon.
Examples of suitable non-polar hydrocarbons include C4-C10 linear or branched alkanes, cycloalkanes and aromatics. More specifically, a non-polar alkane can be isopentane, hexane, isohexane, n-heptane, octane, nonane, or decane; a non-polar cycloalkane such as cyclohexane; or an aromatic such as benzene, toluene, or ethylbenzene. Mixtures of different non-polar hydrocarbons can also be used.
The support slurry can be heated both during and after mixing of the support particles with the non-polar hydrocarbon solvent, but at the point when either or both of the catalysts are combined with the support slurry, the temperature of the slurry should be sufficiently low so that neither of the catalysts are inadvertently deactivated. Thus, the temperature of the support slurry (e.g., silica slurry) is preferably maintained at a temperature below 90xc2x0 C., for example, from 25 to 70xc2x0 C., or from 40 to 60xc2x0 C. in another embodiment.
Gas Phase Polymerization Process
The bimetallic catalysts, and more particularly, the supported bimetallic catalyst composition, described herein are preferably used to make bimodal polyolefin compositions, that is, compositions having a bimodal molecular weight distribution; in a particular embodiment, the bimetallic catalysts described herein are used in a single polymerization reactor to make the bimodal polyolefin composition. Once the supported bimetallic catalyst composition is prepared, as described above, a variety of processes can be carried out using that composition. Among the varying approaches that can be used include procedures set forth in U.S. Pat. No. 5,525,678 in which those processes are modified in accordance with the inventions claimed herein, for example, involving the high fluidized bulk density as described herein. The equipment, process conditions, reactants, additives and other materials will of course vary in a given process, depending on the desired composition and properties of the polymer being formed. For example, the processes discussed in any of the following patents can be used: U.S. Pat. Nos. 6,420,580; 6,388,115; 6,380,328; 6,359,072; 6,346,586; 6,340,730; 6,339,134; 6,300,436; 6,274,684; 6,271,323; 6,248,845; 6,245,868; 6,245,705; 6,242,545; 6,211,105; 6,207,606; 6,180,735; and 6,147,173.
More particularly, the process of the present invention is directed toward a gas phase polymerization process of one or more olefin monomers having from 2 to 30 carbon atoms, from 2 to 12 carbon atoms in a more particular embodiment, and from 2 to 8 carbon atoms in yet a more particular embodiment. The invention is particularly well suited to the polymerization of two or more olefin monomers of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 4-methyl-1-pentene, 1-isobutene, 1-isobutene and 1-decene.
Other monomers useful in the process of the invention include ethylenically unsaturated monomers, diolefins having 4 to 18 carbon atoms, conjugated or nonconjugated dienes, polyenes, vinyl monomers and cyclic olefins. Non-limiting monomers useful in the invention may include norbornene, norbornadiene, isobutylene, isoprene, vinylbenzocyclobutane, styrenes, alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene and cyclopentene.
In the most preferred embodiment of the process of the invention, a copolymer of ethylene is produced, where with ethylene, a comonomer having at least one xcex1-olefin having from 4 to 15 carbon atoms, from 4 to 12 carbon atoms in yet a more particular embodiment, and from 4 to 8 carbon atoms in yet a more particular embodiment, is polymerized in a gas phase process.
In another embodiment of the process of the invention, ethylene or propylene is polymerized with at least two different comonomers, optionally one of which may be a diene, to form a terpolymer.
Typically in a gas phase polymerization process a continuous cycle is employed where in one part of the cycle of a reactor system, a cycling gas stream, otherwise known as a recycle stream or fluidizing medium, is heated in the reactor by the heat of polymerization. This heat is removed from the recycle composition in another part of the cycle by a cooling system external to the reactor. Generally, in a gas fluidized bed process for producing polymers, a gaseous stream containing one or more monomers is continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. The gaseous stream is withdrawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer product is withdrawn from the reactor and fresh monomer is added to replace the polymerized monomer. (See for example U.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749, 5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661 and 5,668,228.)
The reactor pressure in a gas phase process may vary from 100 psig (690 kPa) to 500 psig (3448 kPa) in one embodiment, from 200 psig (1379 kPa) to 400 psig (2759 kPa) in a more particular embodiment, and from 250 psig (1724 kPa) to 350 psig (2414 kPa) in yet a more particular embodiment.
The reactor temperature in a gas phase process may vary from 30xc2x0 C. to 120xc2x0 C. in one embodiment, from 60xc2x0 C. to 115xc2x0 C. in a more particular embodiment, from 70xc2x0 C. to 110xc2x0 C. in yet a more particular embodiment, and from 70xc2x0 C. to 95xc2x0 C. in yet a more particular embodiment, or as set out further below.
In an embodiment of the invention, the process is operated by introducing a carboxylate metal salt such as aluminum stearate or other metal-fatty acid compound into the reactor and/or contacting a carboxylate metal salt with the catalyst system of the invention prior to its introduction into the reactor.
The xe2x80x9ccatalyst systemxe2x80x9d useful in the gas phase polymerization process of the invention includes the first and second catalyst components, making up a bimetallic catalyst, and one or more activators. The bimetallic catalyst is activated by any suitable means known in the art, either before introduction into the polymerization reactor or in situ. The supported bimetallic catalyst is fed to the reactor in a dry (no diluent) state in a particular embodiment. In another embodiment, the bimetallic catalyst is suspended in a diluent (e.g., C5 to C15 hydrocarbon) comprising from 5 wt % to 100 wt % mineral oil or silicon oil and fed into the reactor.
The gas-phase process of the present invention includes contacting the catalyst system (including catalyst components and activators, and optionally, a support) with monomers in a reactor vessel of desirable configuration to form a polyolefin. In one embodiment, the contacting may take place in a first reactor vessel, followed by transfer of the formed polymer into another second, third etc. reactor vessel to allow further polymerization, optionally by adding the same or different monomers and optionally by adding the same or different catalyst components, activators, etc. In a particular embodiment of the present invention, the bimetallic catalyst system is contacted with monomers in a single reactor vessel (or xe2x80x9creactorxe2x80x9d), followed by isolation of a finished polyolefin resin.
For example, a gas phase polymerization process claimed herein may include use of a continuous cycle in which a cycling gas stream (i.e., a recycle stream or fluidizing medium) is heated in the reactor by the heat of polymerization. This heat can be removed from the recycle stream in another part of the cycle by a cooling system that is external to the reactor. In a gas fluidized bed process for producing polymers, a gaseous stream containing one or more monomers can be continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. The gaseous stream is preferably withdrawn from the fluidized bed and then recycled back into the reactor. Polymer product can be withdrawn from the reactor and fresh monomer added to replace the polymerized monomer. (See for example U.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749, 5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661 and 5,668,228)
The reactor pressure in a gas phase process may vary from 100 psig (690 kPa) to 500 psig (3448 kPa) in one embodiment, from 200 psig (1379 kPa) to 400 psig (2759 kPa) in a particular embodiment, and from 250 psig (1724 kPa) to 350 psig (2414 kPa) in yet a more particular embodiment.
In one aspect of the invention, the voidage of the gas phase reactor is desirably controlled. In one embodiment, the polymerization process of the invention is characterized as a process of polymerization using a bimetallic catalyst wherein the voidage of the fluidized bed gas phase reactor is maintained at less than 40%. This can be accomplished by any suitable means such as by, for example, adjusting the hydrogen level in the reactor or reactors. The voidage of the reactor can be described in the equation below (A):                     Voidage        =                              SBD            -            FBD                                SBD            -                          gas              ⁢                              xe2x80x83                            ⁢              density                                                          (        A        )            
wherein SBD is the xe2x80x9csettled bulk densityxe2x80x9d of the formed resin granules in the reactor; FBD is the xe2x80x9cfluidized bulk densityxe2x80x9d, which is the density of the resin granules in the reactor; and xe2x80x9cgas densityxe2x80x9d is simply the density of the gas in the reactor. The FBD is the ratio of the measured pressure drop upward across a centrally fixed portion of the reactor to the height of the fixed portion. For FBD measurements in the present invention, the pressure drop of the fluidized bed is measured from a point slightly above the distributor plate to a point about midway up the fluidized bed. The pressure drop divided by the height difference between the pressure taps, with suitable factors for converting the units of measure, yields FBD. The measurements cited herein are reported as averages covering several hours of operation near the end of each test. As noted therein, the FBD is a mean value, which may be greater or less than the localized bulk density at any point in the fixed reactor portion. Since the gas density is diminishingly small, the equation describing voidage can be simplified to the following (B):                     Voidage        =                  1          -                      FBD            SBD                                              (        B        )            
Certain specific embodiments of the invention are advantageously directed to a process having fluidized bulk density (FBD) that is higher than other bimodal polyolefin polymerization processes. A high FBD (or low voidage) can have benefits in a gas phase polymerization process, since higher FBD generally means higher catalyst productivity due to the higher residence times allowable in such a reactor. A high FBD also provides for advantages for restarting a commercial-scale reactor when a gas phase polymerization cycle is interrupted by extraneous factors. For example, a low FBD corresponds to excessive bed expansion during the restarting process, and can sometimes even make the restart process unsuccessful.
As used herein, the term xe2x80x9cfluidized bulk densityxe2x80x9d (FBD) has the same meaning given that same term in U.S. Pat. No. 5,436,304, in which the term is defined as the ratio of the measured pressure drop upward across a centrally fixed portion of the reactor to the height of the fixed portion, for example, a xe2x80x9cpressure tap vertical separation.xe2x80x9d As noted therein, the FBD is a mean value, which may be greater or less than the localized bulk density at any point in the fixed reactor portion.
All FBD values that are absolute values of fluidized bulk density are expressed in units of lbs/ft3. The values of FBD of the present invention range from 5 to 50 lbs/ft3 in one embodiment, from 7 to 40 lbs/ft3 in a more particular embodiment, and from 8 to 30 lbs/ft3 in yet a more particular embodiment, and from 10 to 25 lbs/ft3 in yet another embodiment, wherein a desirable range for FBD may be any combination of any upper limit with any lower limit.
All SBD values are expressed in units of lbs/ft3. The values of SBD of the present invention range from 10 to 60 lbs/ft3 in one embodiment, and from 12 to 50 lbs/ft3 in a more particular embodiment, and from 14 to 40 lbs/ft3 in yet another embodiment, and from 15 to 35 lbs/ft3 in yet another embodiment, wherein a desirable range for SBD may be any combination of any upper limit with any lower limit.
In one embodiment, the voidage of the reactor is less than 50% (expressing the values above as percentages), and less than 45% in a more particular embodiment, and less than 40% in yet a more particular embodiment, and less than 35% in a particular embodiment, and less than 30% in a more particular embodiment, and less than 20% in a more particular embodiment; and at least 5% in one embodiment, and at least 10% in a more particular embodiment, wherein a desirable range of voidage values may include any combination of any upper voidage limit with any lower voidage limit described herein. Stated another way, the FBD/SBD ratio may have a value of from greater than 0.40 (or 40% when multiplied by 100 as in the data tables) in one embodiment, and greater than 45% in a more particular embodiment, and greater than 50% in yet a more particular embodiment, and greater than 60% in yet a more particular embodiment, and greater than 65% in yet a more particular embodiment; and less than 95% in one embodiment, and less than 90% in yet another embodiment, and less than 85% in yet a more particular embodiment, wherein a desirable range of FBD/SBD values may include any combination of any upper FBD/SBD limit with any lower FBD/SBD limit described herein.
It has been found that the voidage can be adjusted to a desirable level when using bimetallic catalyst systems comprising at least one metallocene by adjusting the level of hydrogen in the polymerization reactor. The level of hydrogen in the reactor can be adjusted by adjusting the level of hydrogen in the gas stream that is introduced into the reactor, or stated alternately, adjusting the ratio of hydrogen and ethylene.
In certain specific embodiments, the polymerization reactor temperature is maintained at a certain level to further optimize the voidage at a desirable level. As used herein, the term xe2x80x9creactor temperaturexe2x80x9d can refer to an actual measured temperature (i.e., at a point in time) of a fluidized bed in a reaction zone of a fluidized bed reactor used to carry out a gas phase polymerization; and can also refer to a calculated number that equals an average of a plurality of actual measured temperatures, measured intermittently over a period of time, for example, an average of ten measured temperatures over a four-hour period. In a particular embodiment, the polymerization reactor temperature ranges from 100xc2x0 C., or 99xc2x0 C., or 98xc2x0 C., or 97xc2x0 C., or 96xc2x0 C., or 95xc2x0 C., or 94xc2x0 C., or 93xc2x0 C., or 92xc2x0 C., or 91xc2x0 C., or 90xc2x0 C., to 40xc2x0 C., 50xc2x0 C., 60xc2x0 C., 70xc2x0 C., or 80xc2x0 C., or 82xc2x0 C., or 84xc2x0 C., or 86xc2x0 C., or 88xc2x0 C., or 90xc2x0 C., wherein the reactor temperature may be in a range from any combination of any upper temperature limit with any lower temperature limit described herein. Thus, for example, a reactor temperature that averages 97xc2x0 C. for at least a one, two, three, four or more-hour period may be utilized during a continuous gas phase polymerization cycle of the invention in one embodiment.
The voidage (or FBD) may be controlled in one embodiment by adjusting the hydrogen level in the polymerization process. The hydrogen levels (also referred to as hydrogen amounts) are sometimes expressed herein in terms of the molar ratio of H2 to C2 (also H2/C2 or H2:C2), wherein H2 refers to molecular hydrogen, and C2 refers to ethylene. Alternatively, the hydrogen levels discussed herein can refer to the ratio of moles H2 to moles of monomers used in the polymerization reaction, for example, ethylene, propylene and/or butene. Preferably, however, the hydrogen level referenced herein is the molar ratio of hydrogen gas to ethylene monomers. As with reactor temperature, the hydrogen levels referenced herein and in the claims include actual instantaneous measured hydrogen levels, for example, a molar ratio of hydrogen gas to ethylene, or an average hydrogen level, based on measured hydrogen levels taken intermittently over a period of time.
The ratio of hydrogen to ethylene has an upper limit of 0.020 in one embodiment, and an upper limit of 0.018 in another embodiment, 0.015 in yet another embodiment, and 0.012 in a more particular embodiment, and 0.012 in yet a more particular embodiment, and 0.010 in yet a more particular embodiment, and 0.009 in yet a more particular embodiment, and 0.008 in yet a more particular embodiment; and the hydrogen to ethylene ration has a lower limit of from 0.0001 in one embodiment, and 0.001 in yet a more particular embodiment, and 0.004 in yet a more particular embodiment, and 0.005 in yet a more particular embodiment, and 0.006 in yet a more particular embodiment. Thus, for example, the average ratio of a molecular hydrogen to ethylene over a four-hour period is 0.009 or below during a continuous gas phase polymerization cycle in one embodiment. The range of hydrogen levels (molar ratios of H2/C2) may comprise any combination of any upper ratio limit with any lower ratio limit described herein. For example, in a specific embodiment, the molar ratio of the hydrogen gas in the gaseous stream to ethylene in the gaseous stream is from 0.003 to 0.011.
An alkylaluminum compound, or mixture of compounds, such as trimethylaluminum or triethylaluminum is feed into the reactor in one embodiment at a rate of from 10 wt. ppm to 500 wt. ppm (weight parts per million alkylaluminum feedrate compared to ethylene feed rate), and from 50 wt. ppm to 400 wt. ppm in a more particular embodiment, and from 60 wt. ppm to 300 wt. ppm in yet a more particular embodiment, and from 80 wt. ppm to 250 wt. ppm in yet a more particular embodiment, and from 75 wt. ppm to 150 wt. ppm in yet another embodiment, wherein a desirable range may comprise any combination of any upper limit with any lower limit. The alkylaluminum can be represented by the general formula AlR3, wherein each R is the same or different and independently selected from C1 to C10 alkyls and alkoxys.
Also, water may also be fed into the reactor in another embodiment at a rate of from 0.01 wt. ppm to 200 wt. ppm (weight parts per million water feedrate compared to ethylene feed rate), and from 0.1 wt. ppm to 150 wt. ppm in another embodiment, and from 0.5 wt. ppm to 100 wt. ppm in yet another embodiment, and from 1 wt. ppm to 60 wt. ppm in yet another embodiment, wherein a desirable range may comprise any combination of any upper limit with any lower limit described herein.
Bimodal Polymer Product
The polymers produced by the processes described herein, utilizing the bimetallic catalysts described herein, which are preferably bimodal, can be used in a wide variety of products and end-use applications. The polymers produced by the process of the invention include linear low density polyethylene, elastomers, plastomers, high density polyethylenes, medium density polyethylenes, low density polyethylenes, polypropylene and polypropylene copolymers.
Polymers that can be made using the described processes can have a variety of compositions, characteristics and properties. At least one of the advantages of the bimetallic catalysts is that the process utilized can be tailored to form a polymer composition with a desired set of properties. For example, it is contemplated that the polymers having the same properties as the bimodal polymer compositions in U.S. Pat. No. 5,525,678 can be formed. Accordingly, U.S. Pat. No. 5,525,678. Also, the bimetallic catalysts described herein can be used in polymerization processes to form polymers having the same properties as the polymers in the following patents: U.S. Pat. Nos. 6,420,580; 6,388,115; 6,380,328; 6,359,072; 6,346,586; 6,340,730; 6,339,134; 6,300,436; 6,274,684; 6,271,323; 6,248,845; 6,245,868; 6,245,705; 6,242,545; 6,211,105; 6,207,606; 6,180,735; and 6,147,173.
The polymers, typically ethylene based polymers, have a density in the range of from 0.860 g/cm3 to 0.970 g/cm3 in one embodiment, from 0.880 g/cm3 to 0.965 g/cm3 in a more particular embodiment, from 0.900 g/cm3 to 0.960 g/cm3 in yet a more particular embodiment, from 0.905 g/cm3 to 0.955 g/cm3 in yet a more particular embodiment, from 0.910 g/cm3 to 0.955 g/cm3 in yet a more particular embodiment, greater than 0.915 g/cm3 in yet a more particular embodiment, greater than 0.920 g/cm3 in yet a more particular embodiment, and greater than 0.925 g/cm3 in yet a more particular embodiment.
The polymers have a molecular weight distribution, a weight average molecular weight to number average molecular weight (Mw/Mn) of from 5 to 80 in one embodiment, and from 10 to 60 in a more particular embodiment, and from 15 to 55 in yet a more particular embodiment, and from 20 to 50 in yet a more particular embodiment.
The polymers made by the described processes have a melt index (MI) or (I2, as measured by ASTM D-1238, 190/2.16) in the range from 0.01 dg/min to 1000 dg/min in one embodiment, from 0.01 dg/min to 100 dg/min in a more particular embodiment, from 0.02 dg/min to 50 dg/min in yet a more particular embodiment, and from 0.03 dg/min to 0.1 dg/min in yet a more particular embodiment.
Polymers made by the described processes have a melt index ratio (I21/I2) (I21 is measured by as measured by ASTM-D-1238, 190/21.6) of from 40 to less than 500 in one embodiment, from 60 to less than 200 in a more particular embodiment. Expressed differently, polymers made by the described processes have a melt index ratio of from greater than 40 in one embodiment, greater than 50 in a more particular embodiment, greater that 60 in yet a more particular embodiment, greater than 65 in yet a more particular embodiment, and greater than 70 in yet a more particular embodiment.
In certain embodiments, propylene based polymers can be produced using the processes described herein. These polymers include atactic polypropylene, isotactic polypropylene, hemi-isotactic and syndiotactic polypropylene. Other propylene polymers include propylene block or impact copolymers. Propylene polymers of these types are well known in the art see for example U.S. Pat. Nos. 4,794,096, 3,248,455, 4,376,851, 5,036,034 and 5,459,117.
The polymers of the invention may be blended and/or coextruded with any other polymer. Non-limiting examples of other polymers include linear low density polyethylenes produced via conventional Ziegler-Natta and/or metallocene-type catalysis, elastomers, plastomers, high pressure low density polyethylene, high density polyethylenes, polypropylenes and the like.
Polymers produced by the process of the invention and blends thereof are useful in such forming operations as film, sheet, pipe and fiber extrusion and co-extrusion as well as blow molding, injection molding and rotary molding. Films include blown or cast films formed by coextrusion or by lamination useful as shrink film, cling film, stretch film, sealing films, oriented films, snack packaging, heavy duty bags, grocery sacks, baked and frozen food packaging, medical packaging, industrial liners, membranes, etc. in food-contact and non-food contact applications. Fibers include melt spinning, solution spinning and melt blown fiber operations for use in woven or non-woven form to make filters, diaper fabrics, medical garments, geotextiles, etc. Extruded articles include pipes, tubing, medical tubing, wire and cable coatings, geomembranes, and pond liners. Molded articles include single and multi-layered constructions in the form of bottles, tanks, large hollow articles, rigid food containers and toys, etc.